/// <summary>
/// Angle in degrees between two directions. The angle is positive if the direction passed as second parameter points at the left of the first one
/// (considering the first one as a vector pointing forward). The angle is negative otherwise.
/// </summary>
/// <param name="dir1"></param>
/// <param name="dir2"></param>
/// <returns> Returns an angles between two directions. </returns>
static public double AngleBetweenDirections(Vector2D dir1, Vector2D dir2)
{
Vector2D dir1norm = dir1.Normalized();
Vector2D dir2norm = dir2.Normalized();
double dot = dir1norm.Dot(dir2norm);
double angle = Math.Acos(dot) * 180 / Math.PI;
// If the coss product vector points down, than dir2 poitn to the left relatively to dir1
if (dir1.Cross(dir2) > 0)
angle *= -1;
return angle;
}
static public Vector2D Direction(Vector2D fromPoint, Vector2D toPoint) {
Vector2D result = new Vector2D(0, 0);
result.X = toPoint.X - fromPoint.X;
result.Y = toPoint.Y - fromPoint.Y;
return result.Normalized();
}
